Hodgkin lymphoma (HL) is a neoplasm of lymphoid tissue that is defined histopathologically by the presence of the malignant Hodgkin-Reed—Sternberg (HRS) cells. The characteristic surface antigen expressed on HRS cells is CD30. There are an estimated 8,000 new HL cases diagnosed annually in the United States and Canada. Advances in the use of combined chemotherapy and radiotherapy in HL over the past half-century have resulted in a durable remission rate of approximately 70%. However, these multi-agent regimens confer a significant morbidity on patients, including secondary malignancies, cardiac disease, and infertility. Furthermore, approximately 30% of patients presenting with HL will become refractory to initial therapy or will relapse. Salvage chemotherapy regimens and autologous stem cell transplant (ASCT) are secondary options for these patients, but both are associated with significant morbidity and limited long term disease control. Patients who relapse after ASCT or are ineligible for salvage therapy have a very poor prognosis. Currently, there is a lack of well-tolerated, efficacious treatment options for these patients. Thus, there continues to be an unmet medical need for patients suffering from HL and other CD30 expressing cancers. The present invention addresses this and other needs.